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An experimental study was performed on the application of the digital image correlation (DIC) technique to characterize aircraft components for which accurate time information is required. This study builds an aircraft external measurement system based on Stereo DIC. This system obtains real-time satellite time information from a GPS clock source and transmits it to a trigger unit. A camera acquires this information and displays it on the image. This solves the problem that some closed laboratories can use only computer time and cannot obtain accurate satellite time when using camera measurements. Moreover, we verify the reliability and accuracy of this approach, finding an average angular accuracy of better than 0.02 degrees and a relative error of less than 1%. Using the binocular Stereo DIC system, the accuracy of the measurements is clarified for specific conditions. Furthermore, we use this system to measure simulated aircraft landing gear, which moves at an angular velocity of 52.4 °/ s over a distance of 5 m with a wide field of view of 16.8°. The satellite time information acquired by the camera and the time information of the captured time targets are highly stable. The system’s reliability is demonstrated for use in practical engineering, contributing to the engineering application of Stereo DIC for external aircraft measurements.

In this paper, the fatigue energy dissipation of Gravity Casting (GC) and Laser-based Powder Bed Fusion (LPBF) AlSi10Mg alloys under cyclic loading are investigated. The increase in surface temperature related to the energy dissipation effect is decoupled and used to predict the fatigue limits of GC and LPBF AlSi10Mg alloys as being 55.8% UTS and 33.9% UTS, respectively. The energy dissipation rate is obtained by solving the one-dimensional thermal diffusion problem. This energy dissipation is separated into related and unrelated fatigue damage using polynomial function fitting. The energy dissipation related to fatigue damage for LPBF specimens is observed to be higher than that of GC specimens, which indicates worse fatigue performance. The fatigue damage entropy is employed to predict the fatigue life of both GC and LPBF AlSi10Mg alloys, which has a good agreement with the results of a traditional fatigue experiment.

In the field of civil aircraft flight test, the speed of aircraft is one of the most important parameters. Generally, there are different methods for the measurement of aircraft speed, including differential GPS measurement, photoelectric theodolite measurement, etc. However, each of them has its own limitations. Commonly, multiple speed measurement methods are used simultaneously to verify each other in important flight test mission. In order to enrich the aircraft speed measurement methods, this paper proposes an aircraft speed measurement method based on computer vision of high-speed camera. The method utilizes the similarity transform model in computer vision theory, and can measures the speed of the aircraft in the world coordinate system. Then, an analysis method of theoretical speed measurement accuracy based on the speed measurement method is proposed by the paper. Finally, in the actual flight test, the method is used to measure the heading speed of the aircraft. Comparing the measurement results of the differential GPS system and the measurement method proposed in this paper, which verifies the accuracy and of the method. The method can be applied not only in the field of flight test but also in a wider range of engineering applications.

Psoriasis is a chronic, non-infectious skin disease affects 2–3% of the population worldwide. In order to find genes possibly cause this skin disease, we re-analyzed the gene expression data-sets from three published studies. We compared the gene expression profiles between lesional psoriatic skin (PP), uninvolved psoriatic skin (PN) and normal skin (NN) tissues. We found that compared with in PN and NN tissues, the expression of FOXO1 is significantly repressed and the expression of AURKA, AURKB and EZH2 is significantly up-regulated in PP tissues (P < 0.001). During the treatment of psoriasis patients with TNF-α antagonist Etanercept, the expression of FOXO1 was re-activated and the expression of AURKA and EZH2 was repressed. These results suggest loss of FOXO1 expression and elevated AURKA/B and EZH2 expression in lesional psoriatic tissues have potential contribution to the development of psoriasis. It is worthwhile to test whether the combination of Aurora kinases or EZH2 inhibitors can enhance the therapeutic effects of Etanercept in psoriasis management.

In this study the tungsten–bronze type tetragonal (Ba 1− x Sr x ) 2 NaNb 5 O 15 system as a kind of lead-free ferroelectric ceramics has been synthesized by low-temperature combustion method. Microstructure and dielectric properties of (Ba 1− x Sr x ) 2 NaNb 5 O 15 system were also investigated. X-ray diffraction (XRD) study confirms the formation of single-phase tetragonal compounds in the crystal system at room temperature. The TEM photograph shows that the particles synthesized by low-temperature combustion method are uniform with an average particle size of 30 nm in diameter. Microstructure analysis of the surface of the compounds by scanning electron microscopy (SEM) suggests that small grains distribute uniformly on the surface of the samples. The dielectric constant ( ɛ ) and tangent loss (tan δ ) of the samples have been measured as a function of both frequency (0–1 GHz) and temperature (0–500 °C). Detailed studies of the dielectric properties suggests that they have undergone a phase transition well above the room temperature and it is also found that the compositions with x = 0.6 have the lowest phase transition temperature ( T c ) and the highest dielectric constant at T c under 100 kHz. Moreover, the (Ba 1− x Sr x ) 2 NaNb 5 O 15 synthesized by low-temperature combustion method have better dielectric properties than those prepared by the solid-state reaction.

Poly(vinylideneflouride-hexafluoropropylene) (PVDF-HFP) copolymer films were simultaneously stretched and static electric poled (SSSEP) in seriate mode. The experimental results exhibited that SSSEP greatly enhanced the piezoelectric properties of the PVDF-HFP films and slightly increased the dielectric properties of the films. The maximum piezoelectric coefficient d33 24 pC/N higher than the reported was obtained in these films under optimum condition. Based on the wide angle X-ray diffraction results, the SSSEP films showed more organized crystalline structure than the only stretched films. POLYM. ENG. SCI., 47:1630–1633, 2007. © 2007 Society of Plastics Engineers

Three types of poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) copolymer films were prepared by extrusion, stretching as well as simultaneously stretching and static electric field poling (SSSEP), respectively, and measured by the differential scanning calorimetric, wide angle X-ray diffraction, fourier transformation infrared-attenuated total reflection, and Dynamic mechanical analysis. The experimental results showed that the films prepared by stretching and SSSEP have higher crystallinity and β phase than by extrusion. SSSEP improved the chain orientation enormously both in crystalline and amorphous regions, resulting in the highest storage modulus. Because of the lower β phase content, the extruded films exhibited the lowest piezoelectric coefficient d 33 . For the stretched and SSSEP films, although the β phase content was similar, the d 33 was distinct because of the different potential energy for the rotation of the dipoles. In addition, the SSSEP films gave the maximum d 33 (24 pC/N), higher than the other PVDF-HFP copolymer films that have been reported.

Strontium barium niobate Sr0.5Ba0.5Nb2O6 (SBN50) is the ferroelectric relaxor material for many electronic applications, has been synthesized by low-temperature combustion synthesis process (LCS) according to thermochemical calculations of propellant chemistry theory. We investigated the influence of the containing water quantity, the heating temperature and the pH of precursor solution on the reaction process and the properties of the final products. The influence of the ratio of reactants on the properties of the final products was also investigated. The TG–DTA, XRD, TEM techniques were used to study the composition, structure and morphology of the synthesized powders.

Poly(vinylidene fluoride)(PVDF) films from the melt were uniaxially drawn at different temperatures. The structure and properties of the drawn PVDF films were characterized by WAXD (Wide Angle X-ra...

The redox process of methylene blue has been studied using thin-layer cyclic voltammetry, UV–VIS spectroelectrochemical techniques and in situ EPR. In situ EPR measurements provide direct evidence for the formation of a methylene blue cation radical. The electrode mechanism for methylene blue is discussed.

Poly(vinylidene fluoride) (PVDF), under certain conditions, shows a crystal transition between the alpha (TGT (G) over bar) and beta (TTT) forms, where T, G, and (G) over bar, respectively, denote trans, gauche, and minus gauche. We investigated the mechanism of this crystal transition by FT-TR and X-ray diffraction, which yielded consistent results. We also carried out differential scanning calorimeter experiments.

Human immunodeficiency virus-1 (HIV-1) viral infectivity factor (Vif) is essential for viral replication because of its ability to eliminate the host's antiviral response to HIV-1 that is mediated by the APOBEC3 family of cellular cytidine deaminases. Vif targets these proteins, including APOBEC3G, for polyubiquitination and subsequent proteasome-mediated degradation via the formation of a Cullin5-ElonginB/C-based E3 ubiquitin ligase. Determining how the cellular components of this E3 ligase complex interact with Vif is critical to the intelligent design of new antiviral drugs. However, structural studies of Vif, both alone and in complex with cellular partners, have been hampered by an inability to express soluble full-length Vif protein. Here we demonstrate that a newly identified host regulator of Vif, core-binding factor-beta (CBFβ), interacts directly with Vif, including various isoforms and a truncated form of this regulator. In addition, carboxyl-terminal truncations of Vif lacking the BC-box and cullin box motifs were sufficient for CBFβ interaction. Furthermore, association of Vif with CBFβ, alone or in combination with Elongin B/C (EloB/C), greatly increased the solubility of full-length Vif. Finally, a stable complex containing Vif-CBFβ-EloB/C was purified in large quantity and shown to bind purified Cullin5 (Cul5). This efficient strategy for purifying Vif-Cul5-CBFβ-EloB/C complexes will facilitate future structural and biochemical studies of Vif function and may provide the basis for useful screening approaches for identifying novel anti-HIV drug candidates.